Sorry I haven't kept you guys informed, but it's because I've been doing massive work on this map:
Starting area with mood lighting!
Something in the first big room, alongside an anteroom!
Amazing skylight action!
A creepy staircase!
Buttons, with machinery!
This will do something later!
Hexen Teleports!
The exit will probably be here!
Looking down through the window!

I got fed up with my old map, it wasn't doing anything for me any more. Simply emulating John Romero wasn't really fun.
So I've decided to try and make a truly original map, only loosely inspired by Dmonfear.WAD and Scythe 1/2. Currently it's very sparse, because I'm in the process of "blocking out" the geometry. I've been using curves liberally, because I think what made my old map terrible was the squareness of it.
You start here, looking down a long corridor at a pair of doors and a corner.
There's a red door around the corner.
Going through the double door, you see this weird room.
This will have a key, a bit like E1M2's "U-turn" bit (with the Red Key and Chaingun secret door.) Making the key lower, though, will require finding a switch in an area unbuilt as yet.
Through the Red door is this very blue area, inspired by parts of E1M1-3 and Episode 2. Also The Sky May Be!
I haven't really thought through monster placement, lighting or anything like that as yet - that's the part I have problems with. Advice would be appreciated, as would comments on the style of geometry and basic texturing (grey walls with brown or blue floors, with other areas having colour-coded carpet, will be the theme.)
Be harsh, please!

I've hit a wall on good architecture for a bit now I've linked the map up to the large computer room (I just need to add the maze leading to the key for the exit, and the route to the exit itself) and so I've applied myself to adding monsters. My plan for the map is almost exclusive use of Zombies, Sergeants and Chaingunners with a few Lost Souls for spice - that way, I can get away with no ammo placement and force the player to rely on kills for ammo. There's a Skulltag minigun in a secret just over half-way through the map which would give the player the edge in a nasty fight against 4 Chaingunners and 4 Sergeants in a confined space. Health in the level is reduced to 2 Stimpaks and a single med kit (only on Ultra-Violence, mind!) so you really need to kill fast and keep killing. I didn't feel E1M1 (the orginial) made you feel like you were "Knee Deep in the Dead" so this version will have about 150-200 human monsters in, alongside some heavy firepower.

I've been going through and doing that, actually. I'll put up some pictures in time, but I'm looking mostly for a green-ish map. I may also change the blue carpet for something else.
Also, are you esselfortium from SA?

Sorry I haven't had my say for a while, I've been rather busy.
The reason I'm using a variety of textures is because I felt that different areas of the map could have slightly different styles, so you wouldn't get lost or confused.
Also, I'd like to highlight E2M2 and E2M3 of Back To Basics as examples of maps which use different tech textures in different regions of the map, and which do it well.

I'm using Skulltag with OpenGL set to "mipmap" and the most basic light effects. I'll post some comparison shots using Software rendering, if people like. However, I'm hoping to add some special Skulltag/GZDoom features and so can't really roll back to DOOM2.exe!
I'd agree on lighting. While the awesome shadow effects maps like Hell Revealed and Scythe 2 use are cool, they're a lot of effort for what is basically a workaround, and there's a certain charm in Doom's two-tone lighting.
I probably won't use thousands of monsters/particle effects though - this isn't Deus Vult.

Status Update!
I've done some more work, not a lot though. Just formalising a secret (rather than the "outside passage" secret there's an indoor one) and beginning my take on the "slime room." I always thought E1M1's slime room looked wacky, and didn't jive with the relatively human rest of the map. So my version is going to be a clinical pumping station with some nasty pools of slime about.
The secret. Perhaps it's too powerful? I don't know, I haven't put any enemies in yet!
This may remind you of a similar corridor in E1M1...
But now it's automatic.
And here's the problem. I'm not sure what to do with this room. Aside from a lowered area you can't see here, I'm not sure what else to add to this room. Got any ideas for cool things for a kind of "tech-y" nukage area?

I know everyone probably bases their first proper map on either MAP01 or E1M1, and I apologise for being no different. However, I'd like to think that unoriginal idea aside, my map aspires to something better than WOW.wad or nuts.wad. So, I present a few images of the few rooms I've made so far:
Looking from the start door into my version of the "pillars and windows" room.
Looking from the window end of the big room up to the stairs to the Armor and overlook room. The stairs are now automated and pop up when you walk into the room.
Looking from the overlook room down into the "pillars" room.
Looking across the main room down to the door out (what would usually lead to the "Big Computer Room" and slime room)
Looking back into the main first room from the "Small Computer Room." Not shown in this image is another small door which will lead to a secret "Pump" room.
The outdoor courtyard has been replaced with this big room, which will contain three doors. The one right at the end will link to the main room via a series of passages, there's another one in a side room which will lead to a key you need to exit and the one on the catwalk will lead to the (locked) exit. This room is meant to combine the courtyard secret and the Slime room, and the secret will be somewhere else.
Looking up at the window in the main room. This area is a lot lower (unlike E1M1's courtyard area) vertically and so I find it more interesting.
Looking from the end of the big Computer room towards the side room, and showing part of the "supercomputer" brush model.
The side room itself. I've got my back to the door to show off the control panel and "energy core" brush model.
In terms of play-style, I'm basing this map more on a Doom 2 model (get key, take door you couldn't take before) as opposed to a "enter area, get key on the way, proceed." one. The map uses things like rising staircases, scrolling textures etc which I picked up from .wads like Deus Vult 2 and (of course) Doom 2.
It's probably nothing special, but it's my first serious map and so if people could tell me if it's absolutely horrendous/just about worth keeping on with/doing fine then I'd be real grateful.